Upon checking in we immediately extended for another month.
As others have noted, the location is excellent - within a few minutes of the BTS, which is invaluable when navigating Bangkok traffic and weather. We also found On Nut to be a nice mix of authenticity and creature comforts. Despite being adjacent to a major road, Heide's building sits back enough that it is relatively quiet and peaceful. The services and amenities are good, including the gym in the building, but you're also surrounded by everything else you may need within a few minutes' walk. We are a couple and enjoyed our stay quite a lot and would go back, but like many Thai apartments, bear in mind that they tend to be a bit smaller so long stays should account for this. We rarely heard or saw neighbors on our floor and most building residents seemed to be young Thai professionals, so it was good for work.
Heide is very helpful and responsive and her apartment is beautiful and both well-equipped and serviced. 10/10.